In X-ray diffraction measurement, it may be required to irradiate an X-ray with as high intensity as possible onto a sample. In this case, a conventional rotating anticathode type X-ray generating apparatus would be employed for the X-ray diffraction measurement.
The rotating anticathode type X-ray generating apparatus is configured such that electron beams are irradiated onto the outer surface of the columnar anticathode (target) in which a cooling medium is flowed while the anticathode is rotated at high speed. In comparison with a stationary target type X-ray generating apparatus, the rotating anticathode type X-ray generating apparatus can exhibit extreme cooling efficiency because the irradiating position of the electron beams on the anticathode changes with time. Therefore, in the rotating anticathode type X-ray generating apparatus, the electron beams can be irradiated onto the anticathode in large electric current, thereby generating an X-ray with high intensity.
By the way, since the intensity of the resultant X-ray generated is in proportion to the electric power (current x voltage) to be applied between the cathode and the anticathode, the intensity of the X-ray can be enhanced only to 1.2 kW at a maximum in the conventional rotating anticathode type X-ray generating apparatus when the electron beams are irradiated onto the target at a spot size of 0.1×1 mm, and also only to 3.5 kW at a maximum in an ultrahigh brightness rotating anticathode type X-ray generating apparatus.
In this point of view, such a technique is disclosed in Japanese Patent Laid-open Application No. 11-339704 as heating the anticathode near the melting point thereof with the electron beams and thus, partially melting the electron beam irradiating portion of the anticathode, thereby generating an X-ray with high intensity. With such a technique, however, the X-ray may not be generated stably over a long period of time on the irradiating condition of the electron beams, so that it is required to improve the performance of the conventional X-ray generating apparatus.
[Patent Document No. 1] Japanese Patent Laid-open Application No. 11-339704